Re: vkernel livelocked and core dumped when killed on -HEAD

From:

Rumko <rumcic@xxxxxxxxx>

Date:

Thu, 01 May 2008 00:57:11 +0200

Rumko wrote:
> Matthew Dillon wrote:
>
>>
>> :Tried to cvs checkout the pkgsrc tree and managed to get "intr 1 at
>> :40001/40000 hz, livelocked limit engaged!". After kill-ing it, it core
>> :dumped. The backtrace repeats itself over and over, I uploaded kernel and
>> :kernel.core to leaf:~rumko/crash/vkernel/30.04.2008/
>>
>> Did the vkernel actually lock-up or was it still responding? e.g. did
>> you try ^Z'ing or ^C'ing the checkout? It is quite possible that
>> the IO co-thread actually managed to exceed the livelock limit without
>> it being a bug.
>>
>> The crash was due to the IO co-thread crashing. The IO co-thread took
>> the shutdown signal from the vkernel when you killed it, but since it
>> doesn't have a globaldata context that blew it up.
>>
>> I will mask the shutdown signal on the co-thread to fix the core
>> dumping issue but we still need to investigate the livelock. Have
>> you been able to reproduce it?
>>
>> -Matt
>
> If I remember correctly, it was completely locked-up, but I will retry
> tonight.
Managed to lock up the host machine by dd-ing a large (10GB) file ... but
couldn't get a memory dump (it seems it did not create it) ... I'll continue
with this tomorrow when I'll feel bolder
--
Regards,
Rumko